The authors describe an aptamer based fluorometric assay for the determination of ATP. It is based on deoxyribonuclease I-aided target recycling and signal amplification. The DNA probe consists of two regions (sequences) that represent the capture probe and the signal probe, respectively. In the absence of ATP, the probe is adsorbed by the surface of graphene oxide (GO) via π-stacking interactions. This results in quenching of the fluorescent label (carboxyfluorescein) and protects it from being cleaved by DNase. Upon adding ATP, the probe wil...